There is an example of a window molding disclosed in JP-A-10-35272. FIG. 1 is a perspective view of a portion of a vehicle V in a state of attaching a window molding along a gap between a window pane on a front side of the vehicle and a vehicle body panel. FIG. 8 is a sectional view of a conventional window molding M′ showing a state of attaching the window molding M′ to a window pane G. The window molding M′ is attached to peripheral edge portions of an upper edge and two side edges of the windowpane G on the front side of the vehicle. The window molding M′ covers gaps between the upper edge and the both side edges of the window pane G and a roof panel and both front pillar panels of a vehicle body panel B. The window molding M′ includes a plurality of molding portions extending longitudinally, each attached to the upper edge or the side edge of the window pane G. The molding portion attached to the upper edge of the window pane G and the molding portion attached to the side edge of the window pane are connected at a corner portion Gc of the window pane G. In a state of being attached to the vehicle, viewed from a front side, the window molding M′ has an inverse U-like shape as a whole but slightly widened towards an opening in the U-like shape. Further, in the following explanation, so far as not described particularly, “exterior direction” indicates an outer side of the vehicle in a direction of the thickness of the window pane G, and “interior direction” indicates a side of a vehicle compartment in a direction of the thickness of the window pane G. Further, “outward direction” and “inward direction” indicate directions along a window pane face, a direction of being remote from a center of the surface of the window pane G is referred to as “outward direction” and a direction reverse thereto is referred to as “inward direction” (refer to FIG. 3). The window molding M′ is provided with a molding main body portion 30, a shielding lip portion 40′ and a folded-back lip portion 50′. The molding main body portion 30 is attached to an outer peripheral edge portion 11 of the window pane G while pinching the outer peripheral edge portion 11. The shielding lip portion 40′ shields exterior direction of a gap 1 between the outer peripheral edge portion 11 and the vehicle body panel B. The folded-back lip portion 50′ is formed to fold back at a distal end portion of the shielding lip portion 40′ and is brought into elastic contact with an outer face of the vehicle body panel B.
A simple explanation will be given with regard to a sporadic occurrence mechanism of noise when the window molding M′ includes the folded-back lip portion 50′ with reference to FIG. 1 and FIG. 9. When the vehicle travels at high speed, on an outer side of the window molding M′, air impinging on the window pane G flows at velocity V1 substantially equal to vehicle speed. Meanwhile, on an inner side of the window molding M′, air entering into the gap 1 from around a hood or a fender flows at comparatively slow velocity V2. When comparing outer pressure P1 on the exterior direction of the window molding M′ and inner pressure P2 on the interior direction of the window molding M′, the inner pressure P2 becomes larger than the outer pressure P1 (P2>P1) by the air flow. An air pressure difference (P2−P1) thereof acts on the sealing lip portion 40′ as a force in the exterior direction. When the force becomes larger than an elastic recovery force F1 of the field lip portion 40′, a free end portion 42′ of the sealing lip portion 40′ is floated up from the gap 1. Therefore, air on the interior direction of the window molding M′ is sucked out to the exterior direction. When there is not the air pressure difference (P2−P1), the free end portion 42′ of the sealing lip portion 40′ stops floating up. A pressure variation produced when air on the interior direction of the window molding M′ is sucked out to the exterior direction causes self-excited vibration of the sealing lip portion 40′. The self-excited vibration of the sealing lip portion 40′ is heard by a passenger at the interior direction as noise and therefore, gives unpleasant feeling to the passenger. When the window molding M′ includes the folded-back lip portion 50′, air at the interior direction is prevented from being sucked out to the exterior direction and sporadic occurrence of the noise is prevented. However, when the window moldings attached to a number of unspecified vehicles, there is a concern of occurring the noise owing to a difference in a shape of a portion of the window molding attached to the vehicle.
The inventors have investigated in details not only on a partial constitution of the vehicle attached with the window molding M′ but also on fabricating steps thereof in order to find out cause of sporadically occurring the noise. Meanwhile, the window molding M′ is attached to the vehicle body panel B in accordance with the following steps. (1) A dam rubber 12 is provided at a position on an inner side of the outer peripheral edge portion 11 at a back face of the window pane G by a predetermined dimension by a predetermined method. The dam rubber 12 is provided in a ring-like shape along the gap between the window pane G and the vehicle body panel B and is projected from the back face of the window pane. The window molding M′ is attached to the outer peripheral edge portion 11 of the window pane G to pinch the outer peripheral edge portion 11 by attaching a fitting groove 31 of the molding main body portions 30 to the outer peripheral edge portion 11. The dam rubber 12 is for preventing a sealing material (adhering agent) 13 from flowing out. (2) Next, in an assembling line of the vehicle, the sealing material (adhering agent) 13 is injected in a string-like shape to coat on the back face of the window pane G along an outer periphery of the dam rubber 12. (3) The window pane G is arranged to an window opening 21 of the vehicle body panel B such that the free end portion 42′ of the sealing lip portion 40′ in a bow-like shape of the window molding M′ is brought into contact with an outer face of the vehicle body panel B and is elastically deformed in the exterior direction. Further, the window pane G is brought into contact with a window opening edge portion 24 of the vehicle body panel B while compressing the sealing material (adhering agent) 13. Under the state, the sealing material (adhering agent) 13 is cured to fixedly adhered thereto. In this way, the window pane G is attached to the vehicle body panel B.
In the state of attaching the window pane G to the vehicle body panel B in this way, the gap 1 is formed between an inclined peripheral wall portion 23 continuous to the window opening edge portion 24 of the vehicle body panel B and the outer peripheral edge portion 11 of the window pane G to which the molding main body portion 30 is attached to fit. The sealing lip portion 40′ is arranged to shield the gap 1 from the exterior direction. In a normal attaching state, an opposed face of the sealing lip portion 40′ is opposed to an opposed face of the folded-back lip portion 50′. The folded-back lip portion 50′ and the sealing lip portion 40′ are elastically deformed such that the opposed face of the folded-back lip portion 50′ and the opposed face of the sealing lip portion 40′ become close to each other. The opposed face of the folded-back lip portion 50′ is arranged to be lightly brought into contact with the opposed face of the sealing lip portion 40′ or to maintain a small gap from the opposed face of the sealing lip portion 40′. In this way, the folded-back lip portion 50′ is brought into elastic contact with the outer face of the vehicle body panel B.
Meanwhile, shapes of respective parts of the vehicle body panel, the window molding, the window pane and the like are scatter within ranges of allowable tolerances. When the respective parts are combined to use, there is a possibility that the window panel is attached to the vehicle body panel in a state in which the folded-back lip portion of the window molding is brought into press contact with the sealing lip portion by accumulation of error. It is estimated that when the state of bringing the folded-back lip portion into press contact with the sealing lip portion continues for a long period of time, the opposed faces of the two lip portions are viscously adhered (or adhered) to each other to bring about a state of being similar to a single lip portion as if the two lip portions were integrated. In this case, it seems that similar to a state in which the window molding M′ is not formed with the folded-back lip portion 50′ as shown by a two-dotted chain line in FIG. 9, when the air pressure difference (P2−P1) becomes larger than the elastic recovery force F1 of the free end portion 42′ of the sealing lip portion 40′, the above-described noise is emitted. The viscous adherence (or adherence) of the sealing lip portion and the folded-back lip portion is brought about owing to accuracy and integration accuracy of the respective part shapes. Therefore, it is also conceivable to resolve the viscous adherence (or adherence) of the sealing lip portion and the folded-back lip portion by improving the accuracy and the integration accuracy of the part shapes. However, there is a possibility of posing problems of an increase in product cost, a reduction in productivity and the like. Further, the viscous adherence or the adherence is estimated to be caused by a material of the sealing lip portion and the folded-back lip portion.
It is an object of the invention to provide a window molding formed with a folded-back lip portion capable of preventing sporadic occurrence of noise.